Browsing by Author "Azeiteiro, Ulisses M."
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- The study of bacterioplankton dynamics in the Berlengas Archipelago (West coast of Portugal) by applying the HJ-biplot methodPublication . Mendes, Susana; Fernández-Gómez, M.J.; Galindo-Villardón, M.P.; Morgado, F.; Maranhão, P.; Azeiteiro, Ulisses M.; Bacelar-Nicolau, P.The relationship between bacterioplankton and environmental forcing in the Berlengas Archipelago (Western Coast of Portugal) were studied between February 2006 and February 2007 in two sampling stations: Berlenga and Canal, using an HJ-biplot. The HJ-biplot showed a simultaneous display of the three main metabolic groups of bacteria involved in carbon cycling (aerobic heterotrophic bacteria, sulphate-reducing bacteria and nitrate-reducing bacteria) and environmental parameters, in low dimensions. Our results indicated that bacterial dynamics are mainly affected by temporal gradients (seasonal gradients with a clear winter versus summer opposition), and less by the spatial structure (Berlenga and Canal). The yearly variation in the abundance of aerobic heterotrophic bacteria were positively correlated with those in chlorophyll a concentration, whereas ammonium concentration and temperature decreased with increasing phosphates and nitrites concentration. The relationship between aerobic heterotrophic bacteria, chlorophyll a and ammonium reveals that phytoplankton is an important source of organic substrates for bacteria.
- Zooplankton biomass, abundance and diversity in a shelf area of Portugal (the Berlenga Marine Natural Reserve).Publication . Pardal, Miguel; Azeiteiro, Ulisses M.During November 1997 and May 1998, zooplankton samples were collected with other environmental data along the shelf area of Berlenga marine natural reserve (MNR) (NW Portugal). Copepods contributed > 70 % to the total zooplankton community. In November the dominant species of copepods were Paracalanus parvus, Temora stylifera and Centropages chierchiae with larvaceans and the cladocerans Penilia avirostris also abundant. The meroplankton was dominated by echinoderms. In May the dominant species of copepods were Pseudocalanus elongatus and Acartia clausi, Centropages typicus, and Calanus helgolandicus, with barnacle larvae and the pisces larvae also abundant. The islands influence was represented in the results by the increase in diversity and meroplankton’s relative importance at the sampling stations in the vicinity of the islands.